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The facts are the 413 with same heads cam intake carb... will make






Less power





The 440 will make more power at the low RPM mid range RPM and will be more at higher RPM

The 4.18 bore can make a lot of power, no one is argueing that bore size can not make a lot of power, no one said a 413 will not make a lot of power, just that the 440 will make more when it has the same equiptment, but the simple FACT is that it will not make as much power as the 440s bore size can. The valve will plain and simple be less shrouded in the 440 and will flow more air at virtually every lift includeing LOW lifts. As an aditional bonus with the bigger bore of the 440 you can put a bigger valve in it than you can a 413 and a bigger valve can flow even more at every lift includeing low lifts and will make more power than the port that is restricted to a valve that will fit a 413. The 413 will NOT make more power than a 440 in equally built engines.

If a smaller bore is better than why not build a 383 RB and while you are at it you could throw in some sleeves to make the bores on that even smaller and really make some awesome power

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Big Bores mean big valves, in a moderate stroke
motor. Big carbs are used and as the r's go
up in the motor, air flow is increased. The
velocity is less at low speed in a 440 vs 413.
The slightly smaller valves in the 413 actually
have a better velocity at low speed than the 440.
Flowing more air with better heads works, but
bore/stroke combo of the 413 would favor a good
flowing head with higher intake port velocity.
This is the key to running a strong 413. Like
I said not an upstairs motor, but plenty of
torque to hold it's own anyplace, short of a full
race or class-type motor.